For dojos in California, go to the web pages of the Southern California Kendo Federation and of the Northern California Kendo Federation. I don't have the URL for both these sites... Gomen nasai!! But, just type in the name of each Federation in the Yahoo search engine(Or whatever one you like best.), and the page should come up for each one. They each have a listing of dojos in California.
I hope this helps you find a good dojo!